One of the four horsemen of the evolutionary synthesis of the 1940s, Theodosius Dobzhansky played a crucial role in bridging the gap between theoretical and empirical approaches in genetics. His contributions to the biological species concept and to an understanding the evolutionary dynamics of wild populations of Drosophila were fundamental to the development of modern population genetics and evolutionary thought.

Born in Nemirov, Ukraine, on January 29, 1900, Dobzhansky came of age during the Bolshevik Revolution, but preferring the revolution in biology to the one in politics. After receiving a degree from the University of Kiev in 1921, he stayed on as an instructor in zoology, working initially on the anatomy and systematics of the coccinellid (ladybird) beetles. On a trip to Moscow in 1923 or 1924, however, he obtained stocks of Drosophila melanogaster that had been imported to the USSR by H. J. Muller and altered the taxonomic course of his research. His demonstration of pleiotropic effects in Drosophila soon brought him to the attention of Yuri A. Filipchenko, so that in 1924 -- the year in which he married the evolutionary biologist Natalia (Natasha) Sivertsev -- he was rewarded with a lectureship at the University of Leningrad.

Although his position in the troubled world of Soviet genetics was rising, Dobzhansky sought out an International Education Board fellowship in 1927 to work in the creative hothouse of T. H. Morgan's fly lab at Columbia, following Morgan to Cal Tech two years later. The years at Cal Tech were particularly exciting ones in the history of genetics, as the largely cytogenetic work of Morgan, Calvin B. Bridges, Alfred H. Sturtevant, and H. J. Muller had begun to unravel the mechanisms of inheritance through the use of cytological and developmental techniques. When Dobzhansky joined the group in 1927, its members were busy constructing linkage maps, locating specific genes on chromosomes by statistically analyzing the frequency with which certain traits are inherited together. Furthermore, only a few months before Dobzhansky's arrival, Muller (by this time at the University of Texas) had announced his discovery that x-ray exposure dramatically increased the natural rate of mutation in Drosophila. Not surprisingly, then, Dobzhansky began irradiating flies during the summer of 1928, and he spent the following winter studying the resultant chromosomal aberrations, mapping them by the use of gene markers. His long years dissecting beetles stood him well in the enterprise, for after removing, sectioning, and staining the ovaries of a young female fly, he provided the first cytological proof of the linear arrangement of genes on chromosomes: under the microscope, Dobzhansky saw a piece of the long, rod-like third chromosome attached to the tiny dot-like fourth chromosome. In the Reminiscences, he wrote: "I don't remember whether I emitted a loud yell. No question that I felt that way." Dobzhansky was promoted to full professor in 1936.

The cytological and developmental approach at Cal Tech continued to serve Dobzhansky well into the early 1930s as he worked on the analysis of translocations and the nature of sex determination, however his differences with the Morgan group soon became evident. All along, he had maintained an active field program, roaming into the California deserts, the Yosemite and Sequoia National Parks, and as far away as Alaska and Mexico in search of wild flies. More importantly, however, he began increasingly to conceptualize the major problems in genetics within an evolutionary and populational context. For over a decade, R. A. Fisher, J.B.S. Haldane, and Sewall Wright had been reaching toward a quantitative methodology for uniting Mendelian and Darwinian theory by shifting the locus of study from the individual to the population. Recognizing that morphological change was the product of shifting gene frequencies, Fisher, Haldane and Wright developed sophisticated mathematical models to assess the relative effects of selectional pressure, mutation, and genetic drift on evolutionary change. What they lacked, above all, was empirical weight.

With this in mind, Dobzhansky and Sturtevant recognized that they could use chromosomal inversions in wild populations of D. pseudoobscura to construct phylogenies and to study evolutionary dynamics at a highly refined scale. Simultaneously, in 1935 Dobzhansky began the fundamental task of reformulating the taxonomic and morphological term "species" to bring it into line with evolutionary theory. Aware from his studies of variability in natural populations that morphological similarity could mask considerable genetic variability, he argued that regardless of the degree of morphological differentiation between populations, reproductive isolation was the surest and most biologically meaningful criterion for distinguishing species. The Jessup Lectures he delivered at Columbia University during the fall of 1936 provided him with a unique opportunity to synthesize the enormous amount of observational, experimental, and theoretical genetics he had acquired, interpreted in light of the emerging quantitative population genetics. These lectures were published in 1937 as Genetics and the Origin of Species, quickly becoming a classic in the emerging fields of evolution and population genetics and in the canon of the Neo-Darwinian Synthesis.

In 1940 Dobzhansky accepted a professorship at Columbia University, and moved back to New York. There he became a close friend of the mouse geneticist, L.C. Dunn, collaborating with him on several books, and he developed close working relationships with George Gaylord Simpson and Ernst Mayr, among others. His growing collaboration with Sewall Wright was particularly productive, with Dobzhansky providing the critical empirical tests for Wright's mathematical insights. Together, they devised methods for measuring the forces of natural selection in the laboratory and, further, for studying the interaction of evolutionary forces in natural populations. With the help of his student Bruce Wallace and Wright, Dobzhansky worked out an elaborate theory of population structure based on inherent genetic diversity. It has been said that Dobzhansky's most significant contribution was the demonstration of vast genetic diversity within each species, a diversity that coexists with the uniformity of the molecular model of the gene and the universality of the genetic code.

Dobzhansky traveled widely during his twenty-two years at Columbia: hunting flies in Guatemala, Brazil, Chile, Australia, New Guinea, Egypt, India, Indonesia, and the western United States. He published prolifically on hybrid sterility, developmental rates, enzyme polymorphisms, genetic responses to environmental change, and behavioral phenomena, such as dispersion rates (how far flies actually fly). Among his more frequent collaborators were J. T. Patterson, C. Epling, C. D. Darlington, and his two research assistants, Olga Pavlovsky and Boris Spassky. He left a substantial legacy, as well, through his students, who included Bruce Wallace, R. C. Lewontin, and E. D. Spiess, as well as several colleagues and students from South America, including A. B. da Cuhna, A. R. Cordeiro, C. Malogolowkin-Cohen, and C. Pavan.

Yet as much as Dobzhansky enjoyed the intellectual climate at Columbia, from the late 1940s on he felt underappreciated and afflicted by the grind of university politics. As a result, he abandoned Columbia in 1962 to accept a position at the Rockefeller Institute (soon to become the Rockefeller University), remaining there until his retirement in 1971. At Rockefeller he expanded the scope of his work into behavioral genetics, while continuing his analysis of enzyme polymorphisms in Drosophila willistoni. In 1966, he adopted the still novel technique of gel electrophoresis to assay individual genotypes within a population, contributing to a raging debate with Muller, James Crow, and Motoo Kimura over the amount and significance of genetic variation in natural populations.

Retiring from Rockefeller in 1971, Dobzhansky continued to remain active in the field as an adjunct professor in the department of his former student Francisco J. Ayala at the University of California, Davis. At the time of his death from lymphatic leukemia in 1975, he was actively co-editing the series Evolutionary Biology, collaborating on a textbook dealing with evolutionary topics with Ayala, G. Ledyard Stebbins, and James Valentine, and was engaged in a series of experiments on chromosomal differences between populations of Mexican Drosophila with A. L. de Garay, R. Félix Estrada, L. Levine, J. Powell, and V.M. Salceda.

Summarizing Dobzhansky's career on the basis of his scientific productivity does not quite capture its scope. From his days at Cal Tech onward, Dobzhansky regularly engaged with the philosophical and social implications of his work. His view of scientific progress was essentially Popperian -- "A scientific 'model,'" he wrote to Arthur R. Jensen in 1972, "is tested in attempts to falsify it, and the more steps it stands successfully, the more convincing it is, until finally it is taken as 'truth.'" He also situated himself within the "process" school of philosophy, although he was critical of mainstream Whiteheadian philosophers for having established "a special religion... a non-Christian religion. A sort of Unitarianism on the Whiteheadian basis" (June 15, 1974). For his own part, Dobzhansky was acutely sensitive to criticism of his philosophical (or scientific) work by other scientists, especially with respect to the reception of his popular works Mankind Evolving and The Biology of Ultimate Concern.

Deeply imbued with his faith in the Eastern Orthodox church, and steeped in an evolutionary world view, Dobzhansky held to a transcendent, cosmic evolutionism deeply influenced by the writings of the Jesuit priest, Teilhard de Chardin. His interests drew regularly him into public debates on the intersection of religion and science, criticizing Pope Paul for his antievolutionary views in the 1960s, and assailing the growing tide of Protestant creationsim of the 1960s and 1970s. In 1972, he wrote J. Kunamoto, that for him "The evolution of life, and the evolutionary origin of mankind, are scientifically established as firmly and completely as any historical event not witnessed by human observers. Any concession to anti-evolutionists, suggesting that there are scientific reasons to doubt the facticity of evolution, would be propagating a plain untruth."

The great problems of the century -- totalitarianism and racism -- also weighed heavily on Dobzhansky's conscience. With L.C. Dunn, a political fellow traveler, and later with Ashley Montagu, Dobzhansky produced a number of works on the biology of race, highlighted by the book Heredity, Race, and Society (1946). Dobzhansky argued that modern genetic studies had demonstrated that eugenical claims about the biological basis of personality and behavior were at best grossly simplified, and were more likely simply wrong. A strong critic of eugenics in the interwar period, he continued to combat "scientific" efforts to establish the facticity of racial differences, participating in the debates over IQ during the 1960s and 1970s. He was particularly adamant that a scientist working on projects concerning the genetics of behavior must remain honest and committed to the logic of his discipline, and he often wrote to scientists to remind them of this fact. At the same time, his own experiences in Russia made Dobzhansky keenly aware of the problems of intellectual freedom and the necessity of supporting even unpopular modes of speech. He bore an unwavering hatred for the Soviet system and took an active role in writing about the Lysenko controversy.

The Dobzhansky Papers are a remnant of the correspondence and writings of the geneticist and evolutionary biologist, Theodosius Dobzhansky. Offering far richer documentation for the last decade of his career than the first three, the correspondence (7.5 linear feet) provides insight into Dobzhansky's scientific, philosophical, and social views. Equally valuable are the 54 notebooks (ca.1917-1975) which comprise an almost uninterrupted personal commentary on Dobzhansky's entire career, replete with typescripts of personal letters and short essays sent to colleagues and friends. The collection also contains two unbound volumes of annotated transcripts from the Columbia Oral History Project, 1962; two bound volumes of papers dedicated to him on his 70th birthday; and 1.5 linear feet of photographs.

"There is in this office a letter-filing cabinet," Theodosius Dobzhansky wrote to a friend in 1968, "where letters are kept for some time, usually two or three years, and then most are either discarded or placed on a back shelf" (Dansereau, 1968). The periodic destruction of files which Dobzhansky described was further accentuated by five major moves during his career, once from Russia to the United States and three times across the North American continent. At each remove, he further weeded out materials that he considered superfluous, uninteresting or unimportant. Thus the majority of the surviving papers either date from after his move to Davis in 1971, or reflect those memories he consciously wished to preserve. The majority of letters concern his ongoing genetic projects from 1971 to 1975; philosophical, ethical and religious issues (including problems raised by behavioral genetics and the IQ debate); and political issues, but routine office correspondence is also abundant. Above all, the Papers display the mix of scientific pugnacity and warm personal relationships with friends and former students that characterized Dobzhansky's writing.

The forty-four page summary of Dobzhansky's career prepared by R. C. Lewontin, M. M. Green, F. J. Ayala, and I. M. Lerner for G. W. Beadle's nomination of Dobzhansky to the Nobel Committee in 1975 gives a comprehensive analysis of Dobzhansky's scientific accomplishments, and contains his complete bibliography, 1918-1975.

Physical description

12.25 linear feet

12.25 linear feet

Provenance

The Dobzhansky Papers have come to the APS in several distinct donations. The bulk arrived as a bequest of Theodosius Dobzhansky in 1976, with later accruals from Ernst Mayr (Series II) and Francisco J. Ayala.

Photocopies of Dobzhansky's correspondence sent to Vavilov (1931), Filipchenko (1925-1930), and Medvedev (1963-1975) were obtained from the M. E. Saltykov-Shchedrin State Public Library, Leningrad (St. Petersburg), Russia.

Preferred citation

Cite as: Theodosius Dobzhansky Papers, American Philosophical Society.

Alternate formats available

The originals of Dobzhansky's correspondence with Filipchenko, Vavilov, and Medvedev housed at the M. E. Saltykov-Shchedrin State Public Library, Leningrad (St. Petersburg), Russia, has been microfilmed on Film 1484.

Other finding aids

The printed version of Bentley Glass' A Guide to the Genetics Collections of the American Philosophical Society contains another biography of Dobzhansky and a further description of the Dobzhansky Papers.

Related material

Correspondence of Thoedosius Dobzhansky with Yuri A. Filipichenko, Nikolai Medvedev, and N.I. Vavilov, in Russian (Mss.B.D65.u).

Dobzhansky appears as a correspondent in many APS collections, some in substantial quantity. Among the more important sources for Dobzhansky are the papers of Hampton Carson (22 items), Ernst Caspari (36 items), Milislav Demerec (171 items), L. C. Dunn (353 letters), I. Michael Lerner (280 items), Ashley Montagu (125 items), George Gaylord Simpson (88 items), Alexander Sokoloff (100 items), Curt Stern (101 items), and Bruce Wallace (114 items).

Bibliography

African American History Note

Scholars of African American history will find interesting material in this collection on the subjects of race and biology, in particular in regards to Dobzhansky's work with L. C. Dunn and Ashley Montagu.

Genetics Note

This collection contains materials which relate to the history of genetics.

• Columbia University.
• University of California, Davis

• Biology, genetics, eugenics
• Drosophila -- Genetics
• Evolution
• Genetics
• Race, race relations, racism
• Russians -- United States